Applicability of Pti5 promoter for design of plant immune signaling sensorRace, Andrej (Avtor) Gruden, Kristina (Mentor) potatoplant immune systemphytohormonesPTI5luciferase assay of promoter activityPlants use diverse hormonal signaling for a coordinated immune response. Salicylic acid (SA) is the main hormone during the defense against biotrophs, while jasmonic acid (JA) is crucial for defense against necrotrophs. On the other hand, abscisic acid (ABA) orchestrates plant response to abiotic stress. Other hormones, such as auxins, play a modulating role. Tools that allow us to monitor these complex signaling pathways and identify genes involved are called biosensors. In this Master’s thesis, we analyzed the functionality of the PTI5 gene promoter in the potato immune response. For this purpose, we first coupled the promoter sequence to the luciferase coding sequence. This allowed us to analyse the effect of SA, JA, ABA, and auxins on PTI5 promoter activity after transiently transforming Nicotiana benthamiana plants with the construct. The method used was luciferase assay. The results showed that the promoter activity was induced upon treatment with medium to high doses of SA, while auxins, hormones that usually counter SA-dependent stress response, repressed PTI5 promoter at specific concentrations. There was no reliable evidence that JA and ABA directly influence PTI5 promoter activity. These findings suggest that PTI5 could be used as a biosensor for high SA concentrations. Future research could analyse the effect of simultaneous treatment with SA and JA or ABA to inspect if there is any synergy. We also tested if the luciferase assays could be conducted on potato genotypes such as Desiree NahG and Rywal NahG, which would allow us to acquire results on a plant of origin. In addition to hormonal treatments with SA and auxin, we analysed the effect of potato virus Y (PVY) infection on PTI5 promoter activity. However, the transient transformation of these genotypes was so inefficient that no useful information could have been obtained from these results.20222022-09-30 13:55:00Magistrsko delo/naloga141525VisID: 17622COBISS_ID: 133132803sl